Integrate ECA

The issues summary isn't describing the need. Please explain more.

ECA could replace the Message module :

https://ecaguide.org/library/simple/notifications/

It could allow several scenarios:

For example Only a "premium" role can contact users of the site, non-premium can answer but by initiating the discussion.

With ECA you can set up recipes that the admin can activate or deactivate.

It might be possible to create an activity stream by automatically seeing a message, when an account or node is updated, when a comment is posted on the user's content...

Ok, I guess we need to provide some ECA plugins? (not very familiar)